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Chickenpox (Varicella)

Topic Overview

What is chickenpox?

Chickenpox (varicella) is a contagious illness
that causes an itchy rash and red spots or blisters (pox) all over the body. Chickenpox can cause
problems for pregnant women, newborns, teens and adults, and people who have
immune system problems that make it hard for the body
to fight infection.

Chickenpox usually isn't a serious health problem in healthy children. But a child with chickenpox needs to stay home from school. And you may need to miss work in order to care for your child.

After you have had chickenpox, you aren't
likely to get it again. But the virus stays in your body long after you get
over the illness. If the virus becomes active again, it can cause a painful
viral infection called
shingles.

What causes chickenpox, and how is it spread?

Chickenpox is caused by the varicella-zoster virus. It can spread easily.
You can get it from an infected person who sneezes, coughs, or shares food or
drinks. You can also get it if you touch the fluid from a chickenpox
blister.

A person who has chickenpox can spread the virus even
before he or she has any symptoms. Chickenpox is most easily spread from 2 to 3
days before the rash appears until all the blisters have crusted over.

You are at risk for chickenpox if you have never had the illness and haven't had the chickenpox vaccine. If someone you live with gets chickenpox, your
risk is even higher because of the close contact.

What are the symptoms?

The first symptoms of
chickenpox usually develop about 14 to 16 days after
contact with a person infected with the virus. Most people feel sick and have a fever, a decreased appetite,
a headache, a cough, and a sore throat. The
itchy chickenpox rash usually appears about 1 or 2 days
after the first symptoms start.

After a
chickenpox red spot appears, it usually takes about 1 or 2 days for the spot to
go through all its stages. This includes blistering, bursting, drying, and
crusting over. New red spots will appear every day for up to 5 to 7
days.

It usually takes about 10 days after the
first symptoms before all blisters have crusted over. This is when the person with chickenpox can return to day care, school, or work.

How is chickenpox diagnosed?

Your doctor will ask
you about your symptoms and will examine you. This usually gives your doctor
enough information to find out if you have chickenpox.

A healthy child with chickenpox symptoms may not need to visit a doctor. You may be
able to describe your child's symptoms to the doctor over the phone.

Teenagers, adults, pregnant women, and people with
health problems need to see a doctor for chickenpox. This is especially
important for pregnant women, since chickenpox during pregnancy can cause
birth defects or serious newborn infection.

How is it treated?

Most healthy children and
adults need only home treatment for chickenpox. Home treatment includes resting
and taking medicines to reduce fever and itching. You also can soak in oatmeal
baths to help with itching.

People with long-term diseases or
other health problems may need more treatment for chickenpox. They may need
immunoglobulin treatment (IG) or antiviral medicine.
Your doctor can give you these soon after you are exposed to the virus to help
you feel better sooner.

How can you prevent chickenpox?

You can prevent chickenpox with the
chickenpox vaccine. Children get the chickenpox vaccine as part of their routine immunizations.

If you
have been around a person who has the virus and you have not had chickenpox or
the vaccine, you still may be able to prevent the illness. Get a shot of
chickenpox antibodies (immunoglobulin) or the vaccine right away.

Cause

The varicella-zoster virus, one of
the herpes viruses, causes
chickenpox infection. The same virus that causes
chickenpox also causes
shingles (herpes
zoster).

How it is spread

The chickenpox virus can spread
easily from one person to another. It most often spreads through the
respiratory tract, such as mucous membranes of the mouth and nose. You also can
get chickenpox through the air from an infected person's sneezing or coughing.
Less often, chickenpox is spread when fluid from a chickenpox blister gets on
your skin.

In rare cases, a person can get chickenpox from the fluid of shingles
blisters.

Symptoms

The first symptoms of chickenpox
include:

A fever of
100.4°F (38°C) to
103°F (39.4°C).

Feeling sick, tired, and sluggish.

Little
or no appetite.

Headache and sore throat.

The first symptoms are usually mild in children, but they
can be severe in teens and adults. These symptoms may continue throughout the
illness.

About 1 or 2 days after the first symptoms of chickenpox
appear, an itchy
rash develops.

What Happens

The first weeks after catching the virus

About 14 to 16 days after
contact with a person infected with the virus, the first symptoms of
chickenpox usually develop. Most people feel sick and have a fever, a decreased appetite,
a headache, a cough, and a sore throat.

Some children get the
chickenpox rash without first having the early
symptoms.

Babies 6 months old and younger may have some protection
against chickenpox from
antibodies passed on by their mothers. So if they are
infected with the virus, they may not have many symptoms.

People
with
weak immune systems may get the first symptoms
of chickenpox sooner than the usual 10 to 14 days after exposure.

Chickenpox is most contagious from 2 to 3 days before the
rash appears until all the blisters have crusted over.

The chickenpox rash

The chickenpox rash usually appears on the upper body about 1
or 2 days after the first symptoms start. The trunk usually is most affected,
and the arms and legs the least. The rash also may spread to the scalp, face, nose,
and mouth. In rare cases, it spreads into the eyelid lining (conjunctiva), into
the clear covering over the eye (cornea), inside the throat, or into the
genital area.

It takes about 1 or 2 days for a chickenpox red spot
(macule) to go through all its stages:

Red or swollen spots or bumps appear and turn into blisters that are filled with clear or cloudy fluid and that look like pimples.

The blisters break open, often leaking fluid.

A dry crust forms over the broken blisters as they heal.

Possible complications

Skin infection is the most common complication for children under age 5.
Skin infection can form after the rash is scratched. Scratching allows bacteria
from the skin or under the fingernails to get into a chickenpox blister. The infection can become serious if it isn't treated. An infected blister also may
leave a scar.

Some
people also are at increased risk of more serious problems from chickenpox. This higher-risk group includes newborns,
teenagers, adults—especially pregnant women—and those who have weak immune systems.

Although you become
immune to the chickenpox virus after you have had
chickenpox, the virus will still be in your body. The virus can later cause
shingles (herpes zoster), usually when you are an
older adult. About 1 in 5 people who have chickenpox will later get
shingles.footnote 1 The shingles vaccine can help prevent shingles or make shingles less painful.

What Increases Your Risk

You are at risk for
chickenpox if you have not had chickenpox or the
vaccine and you:

Live with someone who has
chickenpox.

Are indoors for more than 1 hour with someone
who has chickenpox.

Are in the hospital and share a room with
someone who later gets chickenpox or are cared for by a staff member who
later gets chickenpox.

After you have had chickenpox or the vaccine, you become
immune to the virus. It is possible that you may have
a slight reaction after reexposure, such as a few spots and a slight fever. But
you aren't likely to get chickenpox more than once.

When To Call a Doctor

Call your doctor right away if you or your child with
chickenpox has:

A severe headache or constant vomiting,
sensitivity to bright light, or unusual sleepiness or confusion. These may be
signs of inflammation of the brain (encephalitis).

If you are a teen or adult, are pregnant, or have a weak immune system, it's important to see your doctor as soon as you think you've been exposed to the chickenpox virus. Your doctor may want to give you a medicine that helps protect you from the virus.

A healthy child with chickenpox symptoms may not need to visit a doctor. You may be able to describe your child's symptoms to the doctor over the phone. Then your child won't have to leave the house and risk spreading the virus to others. But it is important to check with your doctor to find out if he or she wants to see your child.

If you go to a doctor's office, ask if you need to
take any precautions when you arrive to avoid spreading the infection. For
example, office staff may take you directly to an exam room when you arrive, rather than have you wait in the lobby.

Exams and Tests

Chickenpox usually can be diagnosed based on how the
chickenpox rash looks. For a healthy child, describing the
rash over the phone to a doctor (rather than visiting the office)
may be all you need to do.

Anyone who is over age 12, or pregnant, or has a weak immune system needs to be checked by a doctor as soon as you suspect chickenpox. When given right away, treatment can help prevent serious complications. For more information, see When to Call a Doctor.

At the doctor's office, your doctor will ask you about your symptoms and will examine you. This usually gives your doctor enough information to find out if you have chickenpox.

Chickenpox during pregnancy

A
woman who has had chickenpox early in her pregnancy may want to have her
fetus checked for birth defects. This can be done with
a
fetal ultrasound during the second trimester.

Find out if you are immune

If you have never had chickenpox or the chickenpox vaccine, you have no immunity against the virus. This means that the virus can make you sick—you can get chickenpox.

If you need to make sure you're immune to the chickenpox virus, a viral test can tell you. It makes sense to get a viral test if you aren't sure you're immune and you:

Plan to or can possibly become pregnant. Having chickenpox immunity prevents
complications of chickenpox during pregnancy.

Are more likely than normal to get severely ill
from chickenpox or to have
complications of chickenpox.

Are required to prove chickenpox immunity for work or school.

Treatment Overview

Treatment for chickenpox depends on your age, your health, how long it's been since you were exposed to the virus, and your symptoms.

A healthy child with chickenpox may need only
home treatment to help relieve itching and monitor fever. For more information, see Home Treatment.

Healthy teens and
adults with chickenpox usually have more severe symptoms than children and are
at higher risk for complications than healthy children. If you are older than age 12, are pregnant, or have a weak immune system, your doctor may want to give you a medicine or vaccine that helps protect you from the virus. For more information, see Medications. Home treatment measures can also help to make you more comfortable.

Prevention

The chickenpox, or varicella, virus spreads easily from person to person. If you have never had chickenpox or the chickenpox vaccine(What is a PDF document?), you have no immunity against the virus. This means that the virus can make you sick.

If you or your child is not immune, you can prevent chickenpox by getting the vaccine. It is recommended for:

All healthy children 12 months of age and older who have not had chickenpox.

Healthy people who aren't sure if they've had the vaccine or chickenpox as a child.

Women who are planning to get pregnant but aren't pregnant yet.

For women who aren't immune, chickenpox and pregnancy can be a dangerous combination. Getting the vaccine when not pregnant prevents complications of chickenpox during pregnancy. Talk to your doctor about the right timing for the vaccine.

You can help
prevent chickenpox by avoiding close contact with people infected with the
virus. This is even more important if you have a
weak immune system. But the virus can spread from
an infected person even before symptoms develop.

Prevent chickenpox after being exposed to the virus

If you have been in contact with a person who has chickenpox and aren't sure if you are immune, a shot of the vaccine may prevent you from having the illness. Or it may make the illness milder.

If you can't have the chickenpox vaccine (for example, during pregnancy) a shot of antibodies (immunoglobulin) or an antiviral medicine may help delay or prevent the chickenpox.

Don't expose children to chickenpox

Before the chickenpox vaccine was available, families often had the virus for weeks at a time as it sickened one person, then the next. To "get it over with," some parents intentionally exposed their children to a child with chickenpox.

Now that the vaccine can protect against the virus, parents have a safer option than exposing their children to chickenpox. Do not expose a child to the chickenpox virus. Even young
children can have serious (though rare) complications from the infection,
including
pneumonia or
encephalitis.

Home Treatment

Most healthy children, teens, and
adults with
chickenpox need only home treatment. But
all teens and adults with chickenpox need to see a doctor. When given right away, treatment can help prevent serious complications.

If you have chickenpox, you don't need to stay in bed. But it's best to
stay quiet and rest. Over-the-counter medicines can help relieve symptoms such as
fever and itching.

Before you give medicine to your sick child, check with your
child's doctor. Because of their small size, children are more sensitive than
adults to the effects of some medicines. Use a measuring spoon or medicine cup
to give liquid medicine to a child. Don't guess the amount or use a regular
table spoon.

Reduce itching

The chickenpox rash itches. Do what you can to control the itch and avoid scratching. Scratching the blisters may
cause a skin infection, or scars may form after the blisters heal.

You can take
steps to
control itching, such as taking oatmeal baths, applying cool compresses, and
taking
antihistamines. Check with your child's
doctor before giving your child antihistamines.

Monitor fever

Fever is your body's normal response to infection. A
higher-than-normal temperature kills bacteria and viruses that cause illness.
Fever medicines stop this natural process, so use one only when fever is causing discomfort.

You can help
relieve a fever with over-the-counter medicine. Follow the package instructions carefully. If you give medicine to your baby, follow your doctor's advice about what amount to give. (Do not give aspirin to people younger than 20, because of the risk of
Reye syndrome, a rare but serious problem).

Call your doctor if you or your child has a fever that lasts longer than 24 hours.

Prevent the spread of infection

If you or your
child has chickenpox, don't return to work, school, or day care until after all
blisters have crusted over, usually about 10 days after the first symptoms
start. To help
prevent spreading chickenpox, stay away from people
who aren't immune.

Medications

Help make chickenpox less severe after you are exposed or have symptoms.

Help relieve chickenpox itch, pain, and fever.

If you (or your child) are not immune to chickenpox and have been exposed to the virus, call your doctor. The right medicine depends on your health, age, how long it's been since you were exposed to the virus, and your symptoms.

Vaccination to prevent chickenpox

To prevent
chickenpox, most people can get the
chickenpox vaccine(What is a PDF document?). To fully protect you, two doses are needed before you're exposed to the virus.

Some people can't get the chickenpox vaccine. They include women who are pregnant and people who have ever had an anaphylactic reaction to gelatin, neomycin, or any other substance in the vaccine.

Medicines to help reduce the severity of chickenpox

Chickenpox vaccine. If you are exposed to
chickenpox and you get the vaccine within 3 days, you may not get
sick, or your illness may be mild. If you can't get the shot within 3 days,
getting it up to 5 days after exposure may still help.footnote 2

Immunoglobulins.Immunoglobulins (IG) help the body's
immune system recognize and destroy harmful bacteria
and viruses in the body, such as the varicella virus. Pregnant women, newborns who are at high risk for getting chickenpox, and people who have certain immune system problems can get a shot of chickenpox IG soon after they are exposed to the virus. It can help prevent infection and help them feel better sooner.

Antiviral medicine. Antiviral medicine, such as acyclovir, is usually used to treat
adults and people who have
weak immune systems. It's used after you start to have
symptoms of chickenpox. Healthy children usually
don't need this medicine when they have chickenpox. It isn't known
whether antiviral medicines reduce a person's chances of having
complications of chickenpox.

Medicines to relieve pain and discomfort

After you
have symptoms of chickenpox, you can take
over-the-counter medicines to help relieve discomfort.
Check with your child's doctor before giving medicine to your child.

Acetaminophen (such as Tylenol) or ibuprofen
(such as Advil) to reduce pain and fever. Follow the package instructions carefully. If you give medicine to your baby, follow your doctor's advice about what amount to give. People over
age 20 also can take aspirin to reduce fever. Do not give aspirin to anyone younger than 20, because of the risk of
Reye syndrome.

Oral
antihistamines (such as diphenhydramine) to relieve itching. Talk to your doctor before using any antihistamine lotions or creams
on yourself or your child. And check with your child's doctor before giving
antihistamine pills to your child.

Your doctor may prescribe
antibiotics to you or your child if you get a skin
infection from chickenpox blisters.

Other Works Consulted

Centers for Disease Control and Prevention (2007).
Prevention of varicella: Recommendations of the Advisory Committee on
Immunization Practices (ACIP). MMWR, 56(RR-4): 1–48.
Also available online: http://www.cdc.gov/mmwr/PDF/rr/rr5604.pdf.

Centers for Disease Control and Prevention (2013). Updated recommendations for use of VariZIG: United States, 2013. MMWR, 62(28): 574–576. Also available online: http://www.cdc.gov/mmwr/preview/mmwrhtml/mm6228a4.htm?s_cid=mm6228a4_e.

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